The thesis examines the Communist Party in Moscow between 1925 and 1932. Its structure, role and membership are studied, together with its relationship with the population of Moscow. A study is also made of politics in the period, with special reference to the oppositions of the 1920's. Four broad problems are discussed. The first is the relationship between the central Party leadership and the Moscow Committee. Second is the role of the grassroots activist in political life. Thirdly, the failure of the oppositions is studied in detail. Finally, popular influence over the Party is examined with a view to discussing how far the revolution had been 'betrayed' in this period. It is found that the Moscow Committee was less autonomous than other regional organs, but that grassroots initiative played an important part in political life. In general, people were reluctant to engage in formal opposition. This largely explains the defeat of the Left and Right oppositions, who failed to attract significant support. The majority of Muscovites remained apathetic or hostile to the Party, but a core of committed activists within it was responsible for many of the period's achievements. To the extent that they supported and even initiated policy, Stalin's 'great turn' included an element of 'revolution from below'.